I have an outgoing and incoming gmail server setup with pop. I only have one incoming server setup with no automated action.

When I send a meeting invitation to someone, that person receives an invite thru mail.
When accepting that invitation, nothing happens in OpenERP. In the OpenERP calendar the meeting says that action is needed for all the invitees. Even the ones that have accepted by replying the mail. All I can do is manually accept in OpenERP.
What do I need to setup to make this work automatically?